Patterns of Chemical Diversity in the Mediterranean Sponge Spongia lamella

The intra-specific diversity in secondary metabolites can provide crucial information for understanding species ecology and evolution but has received limited attention in marine chemical ecology. The complex nature of diversity is partially responsible for the lack of studies, which often target a narrow number of major compounds. Here, we investigated the intra-specific chemical diversity of the Mediterranean sponge Spongia lamella. The chemical profiles of seven populations spreading over 1200 km in the Western Mediterranean were obtained by a straightforward SPE-HPLC-DAD-ELSD process whereas the identity of compounds was assessed by comparison between HPLC-MS spectra and literature data. Chemical diversity calculated by richness and Shannon indexes differed significantly between sponge populations but not at a larger regional scale. We used factor analysis, analysis of variance, and regression analysis to examine the chemical variability of this sponge at local and regional scales, to establish general patterns of variation in chemical diversity. The abundance of some metabolites varied significantly between sponge populations. Despite these significant differences between populations, we found a clear pattern of increasing chemical dissimilarity with increasing geographic distance. Additional large spatial scale studies on the chemical diversity of marine organisms will validate the universality or exclusivity of this pattern

Genetic structure and diversity of the endangered bath sponge Spongia lamella

15 páginas, 5 tablas, 4 figuras.1.Natural populations of Mediterranean commercial sponges have declined substantially over recent decades. The present study explored the distribution of genetic diversity of the endangered bath sponge Spongia lamella along the western Mediterranean and the Portuguese coast. Seven microsatellite markers were used to genotype 231 individuals scattered over nine populations. Basic genetic descriptors and population genetic analyses based on FST test, analyses of the molecular variance (AMOVA), Bayesian clustering, dissimilarity analysis of principal components, and demographic analyses were performed. Genetic differentiation between populations was large and highly significant (global FST = 0.236, P < 0.001). AMOVA and Bayesian analyses showed genetic differentiation among the Atlantic, Balearic, and North Mediterranean areas (FCT = 0.129, P = 0.003). Restricted gene flow owing to short-distance larval dispersal and hydrographical barriers may be playing an important role in genetic differentiation. Recent bottlenecks were also detected for most populations of this sponge. The high levels of inbreeding, sub-structuring, and modest levels of genetic diversity that characterized populations of S. lamella (mean value of genetic diversity 0.512), may compromise its long-term survival. Only one population, from the Gibraltar Strait, presented high levels of genetic diversity (Ceuta, genetic diversity = 0.657), indicating a hotspot of genetic diversity for this species with special relevance for its conservation. Disease outbreaks and overexploitation may be the most important causes of genetic diversity impoverishment of S. lamella. Future conservation guidelines should focus on preserving genetic diversity within genetically impoverished populations by limiting exploitation, and increasing population size. Transplanting specimens from areas with high values of genetic diversity to areas with low diversity values or to areas that have recently experienced demographic declines could reverse the local and global recession of this species.Research funded by grants from the Agence Nationale de la Recherche (ECIMAR), a ‘Beatriu de Pinós’ contract (Comissionat per a Universitats i Recerca from Departament d'Innovació, Universitats i Empresa, Generalitat de Catalunya) and a ‘Juan de la Cierva’ contract (Ministry of Science from the Spanish Government) to R. P-P. Spanish Ministry of Education and Science (projects BENTHOMICS: CTM2010-22218 and SOLID: CTM2010-17755), and the BIOCAPITAL project (MRTN-CT-2004-512301) of the European Union. This is a contribution of the Consolidated Research Group ‘Grupo de Ecología Bentónica’, SGR2009-655 of Generalitat de Catalunya.Peer reviewe

Environmental Heterogeneity and Microbial Inheritance Influence Sponge-Associated Bacterial Composition of Spongia lamella

10 páginas, 5 figurasSponges are important components of marine benthic communities. High microbial abundance sponges host a large diversity of associated microbial assemblages. However, the dynamics of such assemblages are still poorly known. In this study, we investigated whether bacterial assemblages present in Spongia lamella remained constant or changed as a function of the environment and life cycle. Sponges were collected in multiple locations and at different times of the year in the western Mediterranean Sea and in nearby Atlantic Ocean to cover heterogeneous environmental variability. Cooccurring adult sponges and offsprings were compared at two of the sites. To explore the composition and abundance of the main bacteria present in the sponge mesohyl, embryos, and larvae, we applied both 16S rRNA gene-denaturing gradient gel electrophoresis (DGGE) and sequencing of excised DGGE bands and quantitative polymerase chain reactions (qPCR). On average, the overall core bacterial assemblage showed over 60 % similarity. The associated bacterial assemblage fingerprints varied both within and between sponge populations, and the abundance of specific bacterial taxa assessed by qPCR significantly differed among sponge populations and between adult sponge and offsprings (higher proportions of Actinobacteria in the latter). Sequences showed between 92 and 100%identity to sequences previously reported in GenBank, and allwere affiliatedwith uncultured invertebrate bacterial symbionts (mainly sponges). Sequences were mainly related to Chloroflexi and Acidobacteria and a fewto Actinobacteria and Bacteroidetes. Additional populations may have been present under detection limits. Overall, these results support that both ecological and biological sponge features may shape the composition of endobiont bacterial communities in S. lamella.Financial support was provided by the European Union project BIOCAPITAL (MRTN-CT-2004-512301) and the French Agence Nationale de la Recherche on Biodiversity (ECIMAR program ANR- 06-BDIV-001). EOC contribution was supported by grant DARKNESS CGL2012-32747 from the Spanish Office for Science (MINECO).Peer reviewe

Isolation and characterization of microsatellite loci from the endangered Mediterranean sponge Spongia agaricina (Demospongiae: Dictyoceratida).

4 páginas, 1 tabla.The abundance of the bath sponge Spongia agaricinahas decreased drastically in recent years and it is now considered an endangered species under Annex 3 of Bern and Barcelona conventions. We describe eight microsatellite markers and present data on their allelic variation and utility as high resolution genetic markers. We analyzed 36 individuals from two populations and found that the number of alleles per locus ranged between 1 and 7. Observed heterozygosity ranged from 0 to 0.72. We found deviations from Hardy–Weinberg expectations for some loci. We exclusively detected null alleles for those loci that deviated from Hardy–Weinberg expectations. Also, distributions of allele frequencies differed significantly between the two populations, making them suitable for population genetic analyses.Research funded by grants from the Agencia Nationale de la Recherche (ECIMAR), Spanish Ministry of Environment (119/2003), Spanish Ministry of Education and Science (CMT2007-66635) and the BIOCAPITAL project (MRTN-CT-2004- 512301) of the European Union.Peer reviewe

Quantitative comparison of bacterial communities in two Mediterranean sponges

5 páginas.Marine sponges can host in their tissues abundant and diverse bacterial communities. Lack of truly quantitative data on bacterial abundance and dynamics limits our understanding of the organization and functioning of these endobiotic communities. In this technical note, we describe a quantitative polymerase chain reaction approach to quantify the relative abundance of multiple clades of three major sponge-associated bacterial phyla: Chloroflexi, Acidobacteria, and Actinobacteria. To test our approach we used the Mediterranean sponges Spongia lamella and Aplysina aerophoba. We designed five out of the six primer sets used in our study. We tested the new primer sets for specificity and optimized their conditions. Our preliminary data showed that Spongia lamella had larger bacterial abundance than Aplysina aerophoba, except for one clade of Chloroflexi. The two Chloroflexi clades investigated in our study amplified a fraction of the Chloroflexi present in Spongia lamella and most of what is present in Aplysina aerophoba, suggesting a more diverse Chloroflexi population in Spongia lamella than in Aplysina aerophoba. This quantitative technique has a great potential to provide a rapid and robust assessment of sponge microbial target and could contribute to deciphering the complexity of these largely unknown host-symbiont interactions.Peer reviewe

Phytochip: Development of a DNA-microarray for rapid and accurate identification of Pseudo-nitzschia spp and other harmful algal species

Detection of harmful algal blooms has become a challenging concern because of to the direct impacts on public health and economy. The identification of toxic dinoflagellates and diatoms in monitoring programs requires an extensive taxonomic expertise and is time consuming. Advances in molecular biology have allowed the development of new approaches, more rapid, accurate and cost-effective for detecting these microorganisms. In this context, we developed a new DNA microarray (called, Phytochip) for the simultaneous detection of multiple HAB species with a particular emphasis on Pseudo-nitzschia species. Oligonucleotide probes were designed along the rRNA operon. After DNA extraction, the target rDNA genes were amplified and labeled using an asymmetric PCR; then, the amplicons were hybridized to the oligonucleotide probes present on the chips. The total assay from sea water sampling to data acquisition can be performed within a working day. Specificity and sensitivity were assessed by using monoclonal cultures, mixtures of species and field samples spiked with a known amount of cultured cells. The Phytochip with its 81 validated oligonucleotide probes was able to detect 12 species of Pseudo-nitzschia and 11 species of dinoflagellates among which were 3 species of Karenia and 3 species of Alexandrium. The Phytochip was applied to environmental samples already characterized by light microscopy and cloned into DNA libraries. The hybridizations on the Phytochip were in good agreement with the sequences retrieved from the clone libraries and the microscopic observations. The Phytochip enables a reliable multiplex detection of phytoplankton and can assist a water quality monitoring program as well as more general ecological research

Comparative bioaccumulation kinetics of trace elements in Mediterranean marine sponges

10 páginas, 2 tablas, 2 figuras.While marine organisms such as bivalves, seagrasses and macroalgae are commonly used as biomonitors for the environment pollution assessment, widely distributed sponges received little attention as potential helpful species for monitoring programmes. In this study, the trace element and radionuclide bioaccumulation and retention capacities of some marine sponges were estimated in a species-comparative study using radiotracers technique. Six Mediterranean species were exposed to background dissolved concentrations of 110mAg, 241Am, 109Cd, 60Co, 134Cs, 54Mn, 75Se and 65Zn allowing the assessment of the uptake and depuration kinetics for selected elements. Globally, massive demosponges Agelas oroides, Chondrosia reniformis and Ircinia variabilis displayed higher concentration factor (CF) than the erectile ones (Acanthella acuta, Cymbaxinella damicornis, Cymbaxinella verrucosa) at the end of exposure, suggesting that the morphology is a key factor in the metal bioaccumulation efficiency. Considering this observation, two exceptions were noted: (1) A. acuta reached the highest CF for 110mAg and strongly retained the accumulated metal without significant Ag loss when placed in depuration conditions and (2) C. reniformis did not accumulate Se as much as A. oroides and I. variabilis. These results suggest that peculiar metal uptake properties in sponges could be driven by specific metabolites or contrasting biosilification processes between species, respectively. This study demonstrated that sponges could be considered as valuable candidate for biomonitoring metal contamination but also that there is a need to experimentally highlight metal-dependant characteristic among species.We thank the Conseil Régional Provence Alpes Côte d’Azur, the French ANR (www.ecimar.org, ANR-06-BDIV-001) and the European Union through the BIOCAPITAL UE Grant (MRTN-CT-2004-512301) for financial supports (G.G.J and C.N.).Peer reviewe

Co-targeting Mitochondrial Ca2+ Homeostasis and Autophagy Enhances Cancer Cells' Chemosensitivity

International audienceThis is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain